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Soil Borings <br />On January 4, 2022, Live Oak excavated a shallow soil boring near the proposed septic <br />disposal area of the ADU for the purpose of percolation testing. The boring was four <br />inches in diameter, 2.79 feet deep, and was excavated by hand auger. The location of <br />the boring is indicated on Plate 10. <br />The soil in the boring was similar to that described by the Soil Survey. Silty clay with <br />sand was encountered to the full depth of the hole. The soil log is presented on Plate <br />11. <br />Discussion of Soil Lithology <br />Based on the soil observed in the boring, there appears to be moderate potential for <br />percolation in the shallow soil zone. Sandy soils generally have a much greater <br />potential for percolation than fine-grained or cemented soils. However, a percolation <br />test is the only accepted method for determining the suitability of the soils for a septic <br />disposal area. Percolation test results are discussed in the following section. <br />Percolation Test <br />A shallow percolation test was conducted in the proposed septic disposal area of the <br />Site. The soil boring discussed above was used for the percolation test hole. <br />Percolation test procedures conformed to San Joaquin County Environmental Health <br />Department policy. <br />Preparation and Presaturation of Percolation Test Holes <br />After the boring was advanced by hand auger and the soil logged, the test hole was <br />completed for the percolation testing. Approximately two inches of pea gravel were <br />placed in the bottom of the open soil boring, followed by a 2.0 -inch diameter PVC pipe <br />with perforations on the bottom. Pea gravel was then used to backfill a few inches of <br />the annular space. <br />Live Oak presaturated the percolation test hole approximately 24 hours prior to the <br />percolation testing. The hole was filled with water to a height of 12 inches above the <br />bottom of the boring for the presaturation. On the day of testing, the hole was found to <br />be intact and dry. <br />Percolation Test Procedure <br />Live Oak conducted the percolation test for the boring on January 5, 2022. Due to soil <br />conditions observed observed, a four-hour test was selected. Water level <br />measurements were taken every 30 minutes during the four-hour period. The last 30 <br />LOGE 2204 Page 6 <br />